In the field of connectors, there are two families. A first family comprises insertion connectors, and the second family comprises pressure connectors. In both cases, a plug and a socket of an outlet must be brought together. The plug and the outlet have terminations for establishing contact, and electrical cables connected to the terminations. In the pressure connection mode, the contact between conductive portions (normally metal portions) of the plug and corresponding conductive portions of the socket serves to limit the extent to which the socket and the plug can be brought together. The conductive portions of the two parts are brought together "head on", i.e. they are disposed on the "front" ends of the parts in the direction in which they are brought together.
In the insertion contact mode, the plug must be inserted into a cavity in the socket, the contact between the conductive zones of the plug and of the socket generally being established by sliding. The contact force is then lateral, i.e. it acts perpendicularly to the direction in which the plug and the socket are brought together. In the insertion connection mode, the metal portions can be subjected to wear as a result of them sliding against one another. To avoid such wear, "press-down" connectors may be provided. In such connectors, the plug advancing into the socket causes the conductive zones of the socket to move perpendicularly so that, at the end of the stroke, they come into contact with the metal zones on the plug. Pressure connection assemblies may be considered to be press-down devices whose angle of approach is large.
Pressure connectors are not suitable for using to use in outlets but they are very useful for chargers and kits for vehicles. Insertion connectors are not suitable for using to use in chargers and kits for vehicles, but they are well suited to use in outlets.
It is known that it is possible to manufacture combined connectors, i.e. connectors whose sockets are suitable for receiving either pressure contact plugs or insertion contact plugs. In this field, PCT Patent Application WO-A-97/36350 describes a connector that can be used in two manners. In a connector of that type, the metal pressure-connection zones may be extended electrically into metal insertion-connectlon zones.
The development in the use of electrical equipment, in particular in the field of telephony, has led to research into sockets having a variety of functions. For example, consideration has been given to a socket to be installed in a vehicle. In which case, the socket may serve to receive a mobile telephone in order to recharge the battery of the mobile telephone while it rests in the socket. In addition, in the same use, consideration has been given to cause the fact of placing the mobile telephone in the socket to switch over the audio channels (the loudspeaker and the microphone) either to a headset that may be worn by the driver of the vehicle, or to a loudspeaker-phone set installed in the vehicle facing the driver, so as to enable the driver to use the telephone in hands-free mode. Similarly, consideration has been given to connecting a buzzer for the driver, the buzzer replacing audible ringing for the purpose of alerting the wearer of the buzzer that the mobile telephone is receiving a call. Consideration has also been given to using the socket to relay transmission of messages forwarded by the mobile telephone. Such relaying is performed, for example, via a radio link at domestic frequency (e.g. 27 MHz). Finally, for data transmission, and in particular for facsimile transmission, provision is made to connect a microcomputer to the socket which is itself connected to the mobile telephone so as to use the mobile telephone as means for transmitting digital data. As has been observed, mobile telephone connection needs can be very varied. In addition, it has become necessary to organize simultaneous use of links of different types.
A problem encountered with pressure connection assemblies is that, because of the pressure connection principle itself, the contact is of poor quality. That applies even more so when the equipment to be connected is light in weight.